Rotating stent delivery system for side branch access and protection and method of using same

ABSTRACT

A catheter assembly and method of use comprises advancing a catheter having a rotatably mounted balloon relative to the primary guide wire to a vessel bifurcation along first and second guide wires.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional application60/314,467, filed Aug. 23, 2001 the entire contents of which areincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

At least one embodiment of the present invention is directed to thefield of stents and stent delivery systems used to treat stenoses, andmore particularly to stenoses at a bifurcation of a passage.

2. Description of the Related Art

Stent systems are widely used in the treatment of stenoses.Intravascular stents are used in coronary, renal, and carotid arteries,for example, to maintain an open passage through the artery. In patientswhose coronary heart disease consists of focal lesions, stents haveproven effective. For example, where only a single coronary artery isclogged or where there are short blockages in more than a single artery,stents have been used with a great amount of success. An intravascularstent may be positioned in a clogged artery by a catheter and is oftenset in place by inflating a balloon upon which the stent is mounted.This expands the diameter of the stent and opens the previously cloggedartery. The balloon is then deflated and removed from the patient whilethe stent retains an open passage through the artery.

It is recognized, however, that a stent can be deployed in manners otherthan inflating and deflating a balloon. For example, self-expandingstents have been developed in which a cover is removed from over astent, thereby allowing the stent to deploy or spring into place. It isalso contemplated that other deployment mechanisms or means may be usedor developed to advantageously deliver and deploy a stent in position.

Nevertheless, a need still exists for properly delivering and locating astent at a bifurcation. Although efforts have been made to use a stentat bifurcations, these sites have previously been inadequately treatedby a stent. For example, U.S. Pat. No. 5,749,825 is representative of acatheter system that treats stenoses at an arterial bifurcation. Thedisclosure of U.S. Pat. No. 5,749,825 is hereby incorporated byreference.

A stent having different diameters has been proposed to allow placementin both a main passage, such as an artery, and a side branch passage,such as a continuation branch artery. Additionally, these stentsgenerally have a circular opening which allows for unimpeded blood flowinto the side branch artery. However, problems are still encountered inorienting the stent relative to the side branch at the bifurcation ofthe main and branch passages.

Many current devices rely on either passive torque (e.g., pushing thestent forward and allowing the stent that is fixed on the guidewire/balloon to passively rotate itself into place) or creating torquefrom outside of the patient to properly orient the stent delivery systemin the passage. These devices and methods of achieving proper angularorientation have not been shown to be effective in properly placing andpositioning the stent. As will be appreciated and understood by thoseskilled in the art, improper placement of the stent with respect to itsrotational or circumferential orientation, or its longitudinalplacement, could lead to obstruction of the side branch passage. It isimportant to properly position or center an opening formed in thebifurcated stent with the side branch passage to maximize flowtherethrough.

Thus, a need exists for effectively treating stenosed passagebifurcations. This need includes more precise and exact longitudinalplacement and rotational/circumferential orientation of the stent.

Commercially available devices do not maintain side branch access at thetime of stent deployment. This results in the potential for plaque shiftand occlusion of the side branch passage.

It would also be advantageous if stents could be placed across the sidebranch while wire position is maintained thereby helping to protect andsecure further access to the side branch.

All US patents and applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

Without limiting the scope of the invention a brief summary of some ofthe claimed embodiments of the invention is set forth below. Additionaldetails of the summarized embodiments of the invention and/or additionalembodiments of the invention may be found in the Detailed Description ofthe Invention below.

A brief abstract of the technical disclosure in the specification isprovided as well only for the purposes of complying with 37 C.F.R. 1.72.The abstract is not intended to be used for interpreting the scope ofthe claims.

BRIEF SUMMARY OF THE INVENTION

Some embodiments of the present invention include a freely rotatingdeployment system for a stent assembly maintaining side branch accessand protection.

The present invention contemplates a new and improved apparatus andmethod that improves the orientation of a stent by providing a moreexact placement of the stent relative to the side branch passage. This,in turn, leads to better protection of the side branch passage. Thepresent invention has the potential for improvement in trackability ofthe stent delivery system.

At least one embodiment of the invention includes a freely rotatablecatheter balloon surrounding a main hollow member or hypotube. The stentsurrounds both the catheter balloon and the main hypotube. A side branchhollow member or side branch hypotube is attached to the catheterballoon and lies underneath the stent. A distal end of the side branchhypotube exits the stent at a desired longitudinal position while aproximal end of the side branch hypotube extends beyond the proximal endof the stent. At the distal exit point, the stent includes an openingthat, after deployment of the stent, allows for blood flow through theostium of the side branch artery.

The balloon is connected to the stent delivery system. In someembodiments, the balloon is attached both distally and proximally torotate freely about the main hypotube. The rotating members rotate aboutthe main hypotube and are limited longitudinally by first and secondfixed members non-rotatably secured to the main hypotube. The balloonstent assembly rotates freely about the axis defined by the mainhypotube and any radial movement is limited by the main hypotube. Thisconstruction allows the side branch guide wire to direct the stentassembly to rotate freely and passively to the proper circumferentialorientation. Upon inflating the balloon, the fixed and rotated memberssecure the circumferential orientation of the stent delivery system.Thus, the side branch guide wire properly orients the stent deliverysystem in its correct position relative to the side branch.

A primary feature of some embodiments is that at the time of positioningthe stent, the stent will be properly oriented relative to the sidebranch, i.e., a stent delivery system and method that correctlypositions the stent in a bifurcated passage.

Another advantageous feature is side branch protection with the guidewire during stent deployment.

Another benefit of this invention resides in proper alignment of thestent delivery system in a bifurcated passage to achieve correctcircumferential orientation relative to a side branch passage, andsecuring the desired orientation.

Yet another benefit of this invention is the ability to properly placethe stent delivery system longitudinally relative to the side branch.

A further advantage of the system is that tangled wires pose less of aproblem.

These and other embodiments which characterize the invention are pointedout with particularity in the claims annexed hereto and forming a parthereof. However, for a better understanding of the invention, itsadvantages and objectives obtained by its use, reference should be madeto the drawings which form a further part hereof and the accompanyingdescriptive matter, in which there is illustrated and described aembodiments of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

A detailed description of the invention is hereafter described withspecific reference being made to the drawings.

FIG. 1 is a cross-sectional side view of a rotating stent deliverycatheter assembly for stenting an arterial bifurcation in itspre-deployment configuration, with the catheter balloon shown inflated.

FIG. 2 is a perspective view of the stent delivery assembly of FIG. 1shown with a stent disposed about the balloon.

FIG. 3 is a perspective view of the stent delivery catheter assembly ofFIG. 1 as it would appear in the collapsed state prior to having a stentmounted on the balloon.

FIG. 4 is a perspective view of a stent delivery system with the balloonin an inflated state and the side branch hypotube in an open condition.

FIG. 5 is an enlarged view of the distal exit point of the side branchhypotube and the opening of the rotating stent delivery catheterassembly of FIG. 2.

FIG. 6 is a perspective view of a proximal shaft of an alternate stentdelivery catheter assembly having only one rotating joint that is selfsealing when pressure is applied or withdrawn.

FIG. 7 is an enlarged side view of a distal end of the rotating balloonassembly associated with FIG. 6.

FIG. 8 is an enlarged side view of the combined components of FIGS. 6and 7, specifically portions of the distal end of the proximal fixedshaft in FIG. 6 combined with the proximal end of the freely rotatabledistal portion in FIG. 7 creating a rotating stent delivery catheterassembly with a single rotating joint that is self sealing.

FIG. 9 is an enlarged side elevational view of FIGS. 6 and 7 showing thecombined of components of FIGS. 6-8 in their entirety.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. This description is an exemplification of the principles ofthe invention and is not intended to limit the invention to theparticular embodiments illustrated.

For the purposes of this disclosure, like reference numerals in thefigures shall refer to like features unless otherwise indicated.

Referring now to the drawings wherein the showings are for the purposesof illustrating the preferred embodiments of the invention only and notfor purposes of limiting same, FIG. 1 shows a stent delivery system orassembly 10. Assembly 10 includes a first guide member, or main guidewire 12 that extends axially through a first hollow or tubular member14. The first hollow member 14 will also be identified as a mainhypotube, although it will be appreciated that the particular shape orconfiguration of this component may change from that illustrated in thedrawings. The main guide wire 12 is used as the delivery guide of thestent catheter assembly 10 to a stenosed region of a passage such as anartery (not shown). The main hypotube 14 is preferably a hollow cylinderwith openings on both its distal and proximal ends, respectively end 16and end 18, which allows for passage of the main guide wire 12therethrough. A first fixed member, or distal fixed body 20 and a secondfixed member, or proximal fixed body 22 are non-rotatably secured todistal end 16 and proximal end 18 of the main hypotube 14. Althoughdescribed as separate elements, it will be understood that the fixedbodies 20 and 22 and the main hypotube 14 can be separate componentsthat are secured together or an integrally formed assembly if desiredfor ease of manufacture or assembly. The fixed bodies 20 and 22 arepreferably tapered from smaller diameter, axially outer ends to largerdiameter, intermediate ends for reasons that will become more apparentbelow.

A first rotating member or distal rotating member 24 and a secondrotating member or proximal rotating member 26 are axially spaced apartand located between the distal fixed body 20 and proximal fixed body 22.The rotating members 24 and 26 are preferably of the same generaldiameter throughout their length and rotate freely about the axis of themain hypotube 14.

Sealed to the proximal and distal rotating members 24 and 26 areopposite ends of a catheter balloon 28. A distal end 30 of the catheterballoon is sealingly joined to (or integrally formed with) the distalrotating member 24 while a proximal end 32 of the catheter balloon issealingly joined to (or integrally formed with) the proximal rotatingmember 26. Thus, the balloon is free to rotate relative to the mainhypotube, a feature that provides advantages and benefits over knownstent assemblies. It is also contemplated that the rotating members 24and 26 can be formed of sealing or elastomeric material (or incorporatea separate seal member) so that slight axial movement of the balloon 28and of the rotating members 24 and 26 engages and seals against thefixed bodies 20 and 22 upon inflation of the balloon 28. The balloon 28and the rotating members 24 and 26 can hold high pressure and seal atthe ends. It will be appreciated that the rotating members 24 and 26 arepreferably constructed to maintain a cylindrical configuration underpressure so that the balloon 28 is free to rotate relative to the mainhypotube 14 when pressurized.

In some embodiments the stent delivery catheter system further includesan outer hollow/tubular member or outer hypotube 40 received over themain hypotube 14. The outer hypotube 40 is radially spaced from the mainhypotube 14 at a first or proximal end 42 to define an annular space 43through which fluid from an external source (not shown) is introduced toinflate the balloon. In at least one embodiment, a second or distal end44 of the outer hypotube 40 is sealed to the main hypotube 14 so thatfluid cannot escape therefrom. Alternatively, the distal end of theouter hypotube extends only partially into the balloon 28. In addition,one or more openings, or contrast ports, 46 are provided in the outerhypotube 40 at a location within the balloon 28 so that the fluid canenter the cavity defined between the balloon 28 and the outer hypotube40 as illustrated by the directional arrows in FIG. 1. Alternatively,the opening 46 may define the distal end of the outer hypotube 40. In atleast one embodiment, the balloon 28 is fully inflated at the proximalend 42 and then begins to inflate at the distal end 44. The outerhypotube 40 may be advantageously and integrally formed with the firstand second fixed members 20 and 22 for ease of manufacture, although itwill be appreciated that these may be separate members without departingfrom the scope and intent of the invention.

A conventional or specially designed medical device, such as a stent 50,encloses a portion of the catheter balloon 28, such as is shown in FIG.2. The stent 50 is typically a metal sleeve of mesh construction that isadvanced into the stenosis riding on the balloon 28 of the catheterassembly 10. Once properly positioned, the balloon 28 is inflated withan inflation fluid, such as saline and contrast, through the passage 43between the main hypotube 14 and the outer hypotube 40, which expandsthe balloon 28 and expands or radially opens the stent 50 to compress anatheroma that is narrowing the passage wall. Although the balloon 28 issubsequently deflated for removal from the patient with the catheterassembly 10, the stent 50 remains in its expanded state allowingincreased flow through the previously closed/blocked (stenosed ornarrowed) region. Alternatively, a self-expanding stent not requiring aballoon for delivery or deployment can be used without departing fromthe scope and intent of the present invention.

A second or branch tubular member 60, also referred to as a side branchhypotube, is provided between the catheter balloon 28 and the stent 50.As evident in FIG. 2, the side branch hypotube 60 carries or receives aside branch guide wire 62. The side branch hypotube 60 extends from theproximal end of the stent 50 between the stent and balloon and exits thestent at an intermediate longitudinal position through an opening 64.The opening 64 provides for both the exit of the side branch hypotube60, as well as the unobstructed passage of blood flow into the sidebranch passage once the stent has been deployed. It should beunderstood, however, that the side branch hypotube opening 64 could beplaced at any convenient position along the stent.

An enlarged view of the side branch hypotube opening 64 in the stent 50is shown in FIG. 5. The side branch hypotube 60 exits from underneaththe proximal end of the stent. Upon deployment of the stent 50, the sidebranch hypotube opening 64 allows for unobstructed blood flow to theostium of the side branch passage. As will also be appreciated, the sidebranch hypotube 60 is fixed or secured to the exterior of the balloon.Thus, the side branch hypotube 60, balloon 28, and rotating membersfreely rotate as a unit relative to the main hypotube 14 for accurate,passive positioning with the side guide wire and thus accuratepositioning of the stent 50 relative to a saddle point of the bifurcatedpassage. With continued reference to FIG. 2, the catheter balloon 28 isinflated, the stent 50 is deployed, and the rotating members 24 and 26are interlocked with the fixed members 20 and 22 to stop the rotatingaction of the stent delivery system and create a pressure tight system.

The side branch hypotube 60 may also be slit 66 along its longitudinallength to facilitate removal of the side guide wire 62 as is shown inFIGS. 3 and 4. The side branch hypotube 60 is secured to the balloon 28along its length at a circumferential location opposite the longitudinalslit, i.e., diametrically opposite the slit 66. The natural elasticityof the side branch hypotube 60 is utilized so that when the balloon 28is inflated, such as is shown, the side branch hypotube 60 issubstantially cylindrical in shape to enclose the portion of the sideguide wire 62 therein such as is shown in FIG. 2. When the balloon isinflated, it exerts a tensile force on the side branch hypotube 60 thatopens the hypotube 60 along its length, such as in the manner shown inFIG. 4. As a result the side guide wire 62 is released through the slit66. When the balloon 28 is deflated, such as is shown in FIG. 3, theside branch hypotube 60 again adopts a cylindrical conformation wherebythe remainder of the stent delivery system (balloon and catheter) can beeasily removed.

The split side branch hypotube 60 offers another desirable feature. Thesplit hypotube 60 allows for immediate placement of a second ballooninto the side branch for simultaneous “kissing” balloon inflation. Inother words, first and second balloons are simultaneously located in themain and side branch passages such that their proximal ends abut andtheir distal ends are placed in each respective branch. This is to becontrasted with use of an unsplit or solid side branch hypotube whichwould require removal of the first balloon prior to insertion of aballoon in the side branch.

An alternative rotating stent delivery system is illustrated in FIGS.6-9. For purposes of brevity, like components will be referenced by likenumerals with a primed suffix (′) and new elements will be identified bynew numerals.

A proximal shaft is generally well known in the art and may takenumerous forms; however, the proximal shaft 70 shown in FIGS. 6-9preferably includes a bushing 72 at a distal end and a seal 74 comprisedof a soft material. The seal 74 is connected to the proximal shaft 70and, as shown, tapers to a smaller diameter and envelops the mainhypotube 14′, as is shown in FIGS. 8 and 9. Within lumen 76 of theproximal shaft 70, the bushing 72 abuts against an interior distal endof the proximal shaft.

With reference now to FIG. 7, a distal rotating portion of proximalshaft 70 is shown. A separate hypotube 14′ includes a proximal end witha first bushing 80 and a second bushing 82 axially spaced therefromalong the separate hypotube 14′. A second seal 84 comprised of a softmaterial, is connected to the first bushing 80 at the proximal end ofthe separate hypotube 14′. The annular second seal 84 protrudessubstantially parallel along the longitudinal axis of the main hypotubeand extends axially beyond an opening 86 for the main branch guide wire(not shown). Additionally, a third annular seal 88 is shown connected tothe first bushing 80. The third seal 88 has a smaller diameter and liesaxially and radially inward of the second seal 84. The third seal 88 isalso secured to the first bushing 80 of the separate hypotube 14′ andtapers radially inward as it extends longitudinally in a direction awayfrom the separate hypotube 14′, to envelope the main guide wire 12′.

The integration of the proximal end of the separate hypotube 14′ and thedistal end of the proximal shaft 70 is shown in FIG. 8. Particularly,the first and second bushings 80, 82 of the hypotube 14′ are of adiameter that allows them to fit under or within the particularcomponents of the proximal shaft 70. Specifically, the second bushing 82of the hypotube 14′ is distal to the proximal shaft bushing 72 and isenveloped by the first soft seal 74 of the proximal shaft 70. The firstbushing 80 of the hypotube 14′ is adjacent to the bushing 72 of theproximal shaft and is enveloped by the proximal shaft 70.

With continued reference to FIG. 8, the integrated hypotube 14′ andproximal shaft 70 are shown in a freely rotatable position. In thismode, the hypotube 14′ rotates freely while the proximal shaft 70remains fixed. Positive pressure allows the seals 82 and 88 extendingfrom the first bushing 80 of the hypotube 14′, to contact the proximalfixed shaft 70 and main guide wire 12′ hence sealing the balloondelivery system 10′ allowing for all positive pressure to be transferredto the balloon 28′. This provides for expansion of the balloon 28′ anddeployment of a stent such as previously described. Alternatively, as isshown in FIG. 9 negative pressure applied within the shaft 70 willcreate contact between the separate hypotube and the seal 74 of theproximal shaft 70. Also, contact will be created at the distal end ofthe separate hypotube between the soft material and the wire 12′creating a seal there as well. These seals allow for all negativepressure to be transmitted to the balloon allowing for collapse and thenremoval of the balloon.

Thus, it is apparent that a truly unique feature of the invention is afreely rotating stent assembly that provides a more exact placement ofthe stent relative to the side branch passage.

The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon a reading and understanding of this specification. Forexample, the illustrated embodiments use a balloon to expand the stentalthough, as briefly noted above, a self expanding or self deployingstent can be used without departing from the features of the presentinvention. Likewise, using a fixed wire on the distal end of theapparatus is also recognized as being consistent with the features ofthe present invention. Moreover, the preferred embodiments describe aside branch hypotube, either split or unsplit, that is associated withthe side branch guide wire. It will be further appreciated that the sidebranch guide wire could be carried and/or released in a variety of otherways. The invention is intended to include all such modifications andalterations thereof.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

Further, the particular features presented in the dependent claims canbe combined with each other in other manners within the scope of theinvention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g. each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

1. A catheter assembly comprising: an elongate guide member, theelongate guide member extending from a proximal end to a distal end ofthe catheter assembly; an inner tubular member, the inner tubular memberdisposed about a portion of the elongate guide member; an outer tubularmember, the outer tubular member disposed about at least a portion ofthe inner tubular member; a proximal rotatable member and a distalrotatable member, the proximal rotatable member being disposed about aproximal portion of the outer tubular member, the distal rotatablemember being disposed about at least one of the distal portion of theinner tubular member and the distal portion of the outer tubular member,the proximal rotatable member forming a slidable and rotatable fluidseal with the proximal portion of the outer tubular member and thedistal rotating member forming a slidable and rotatable fluid seal withthe at least one of the distal portion of the inner tubular member andthe distal portion of the outer tubular member; and a medical balloonexpandable between a first state and a second state, the medical balloonhaving a proximal end and a distal end, the proximal end of the medicalballoon being engaged to the proximal rotatable member and the distalend of the medical balloon being engaged to the distal rotatable member.2. The catheter assembly of claim 1 wherein the proximal portion of theouter tubular member and the inner tubular member define a space, thespace defining an inflation lumen.
 3. The catheter assembly of claim 2wherein at least a portion of the outer tubular member underlying themedical balloon defines at least one inflation port, the at least oneinflation port in fluid communication with the inflation lumen.
 4. Thecatheter assembly of claim 1 wherein the distal rotatable member isdisposed about the distal portion of the outer tubular member.
 5. Thecatheter assembly of claim 4 wherein the distal portion of the outertubular member is sealingly engaged to the distal portion of the innertubular member.
 6. The catheter assembly of claim 1 further comprising aproximal stop member and a distal stop member, the proximal stop memberbeing fixedly engaged to the proximal portion of the outer tubularmember, the distal stop member being fixedly engaged to at least one ofthe distal portion of the inner tubular member and the distal portion ofthe outer tubular member.
 7. The catheter assembly of claim 6 whereinthe proximal stop member is positioned proximally adjacent to theproximal rotatable member and the distal stop member is positioneddistally adjacent to the distal rotatable member.
 8. The catheterassembly of claim 7 wherein when the medical balloon is expanded fromthe first position to the second position the proximal rotatable memberis moved longitudinally to engage the proximal stop member and distalrotatable member is moved distally to engage the distal stop member. 9.The catheter assembly of claim 1 further comprising a secondary tubularmember, the secondary tubular member being engaged to an externalsurface of the medical balloon.
 10. The catheter assembly of claim 9wherein the secondary tubular member has an open position and a closedposition, in the closed position the secondary tubular member defining asubstantially hollow interior open at both ends, the substantiallyhollow interior defining secondary lumen, the secondary lumenconstructed and arranged to receive a secondary elongate guide membertherethrough, in the open position the secondary tubular member definesa longitudinal opening that exposes the secondary lumen therebyreleasing the secondary elongate guide member from the secondary tubularmember.
 11. The catheter assembly of claim 10 wherein the secondarytubular member is disposed about a secondary elongate guide member, thesecondary tubular member being moveable relative to the secondaryelongate guide member.
 12. The catheter assembly of claim 11 furthercomprising a stent, the stent comprising a substantially hollow tubularmember having a plurality of openings therethrough, the stent beingdisposed about at least a portion of the medical balloon when the stentis in the unexpanded position, the stent being expandable from theunexpanded position to an expanded position, the stent being in theunexpanded position when the balloon is in the first state, the stentbeing in the expanded position when the medical balloon is in the secondstate.
 13. The catheter assembly of claim 12 wherein the stent isselected from the group consisting of a balloon expandable stent, aself-expanding stent and any combination thereof.
 14. The catheterassembly of claim 11 wherein the secondary tubular member is positionedbetween at least a portion of the stent and the medical balloon.
 15. Thecatheter assembly of claim 14 wherein the secondary elongate guidemember exits the secondary tubular member and passes through one of theplurality of openings through the substantially hollow tubular member ofthe stent.